Field of the Invention
The current invention belongs to the domain of industrial handling of layers of products, to be either stacked in a pile on a support like a pallet, or taken from such a stack.
The object of the present invention is a transfer device, for transferring layers between a stack and an external conveyor, and a corresponding method.
Description of the Related Art
Different technologies of layers handling currently exist. For example, U.S. Pat. No. 4,274,780 discloses an installation in which the products arrive in a single column in order to build the layer. A forklift is then moved up or down to bring the layer at the correct height on the stack.
EP2112097 discloses a combination of a conveyor and a pusher to move the layer on a release tool. Said release tool can then move to bring the layer on the top of the stack. The layer is released on the stack by retracting the bottom layer of the release tool.
EP2610197 discloses a layer handling device with a single column, on which both a release tool and a tray move in the vertical direction.
In any of these architectures, a lot of controls are performed to monitor the working process, in either the palletisation way, or the depalletization way, among which: detecting the stack to depalletize, measuring the thickness of the pallet on which the layers will be stacked, measuring the real height of a stack, even while processing, detecting fallen objects, etc.
It is a normal practice to implement one separate sensor dedicated to each detection, mainly because each detection has its own area. This obviously leads to a high number of detectors. Furthermore, in some embodiments, a sensor has both an emitter and a distant receiver, and is made to detect a presence between them. Using such a principle of detection has a high impact on the design of the machine, because both an emitter and a receiver have to be mounted around each surface to look at.